Radiative recombination in GaAs-AlxGa1−xAs quantum dots

We present experimental and theoretical results on the low-temperature luminescence intensity of dry-etched GaAs-AlxGa1−xAs quantum dots. The luminescence intensity was found to decrease by two orders of magnitude with the decrease of dot sizes from 1 μm to 60 nm. Our intrinsic model of the emission yield invokes slower momentum and energy relaxation mechanisms as the lateral dimensions decrease. The additional extrinsic effect considered involves carrier diffusion with a surface nonradiative recombination velocity. Combining intrinsic and extrinsic effects and using a surface recombination velocity of ∼105 cm/s for GaAs, we can obtain a good fit to the data.